Special Pub. 3^+^ superseded by SP 398

U.S. DEP.ARTMENT OF COMMERCE NBS Spec. Publ. 344

National Bureau of Standards Issued March 1971 Washiniiton, D.C. 20234 GENERAL PHYSICAL CONSTANTS

The values of constants t;iven in the table on the other side of this card are taken from Taylor, Parker, and Lan-ienberg. Rev. Mod. Phys. 41, p. 375 (1969). These should be considered interim values pending c.mpletion of the work of the Task Croup on Fundamental Constants of the Committee on Data for Science and Technology. International Council of Scienti6c linions. The Internationai System of Lmts (SI) The International System of Units (SI), established in 1960 by the General Conference of Weights and Measures under

the Treaty of the Metre, is based on: the metre (m) for length, defined as 1 650 763.73 wavelengths in vacuum corresponding to the transition 2p, 0 — 5(4 of krypton 86; the kilogram (kg) for mass, defined as the mass of the prototype kilogram at Sevres, France; the second (s) foi time, defined as the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of cesium 133; the kelvin (K) for temperature, defined

as 1/273.16 of the thermodynamic temperature of the triple point of water; the ampere (A) for electric current, defined

as the current that, if flowing in two infinitely long parallel wires in vacuum separated by one metre would produce a force between the wires of 2 x 10 ' newton per metre of length; and the candela (cd) for luminous intensity, defined as the lumi- nous intensity of 1/600 000 square metre of a blackbody at the temperature of freezing platinum. DEFINED VALUES AND CONVERSION FACTORS

Atomic mass unit (u) 1/12 the mass of an atom of the '-C nuclide Standard acceleration of free fall 9.806 65 m/s-, 980.665 cm/s- Standard atmosphere 101 325 N/m^ 1 013 2.50 dyn/cm^ Thermochemical calorie 4.184 J, 4.184 x 10' ergs

Int. Steam Table calorie 4.1868 J, 4.1868 X 10' ergs

Liter 0.001 cubic metre Mole (mol) amount of substance comprising as many elementary

entitles as there are atoms in 0.012 kg of 'C

Inch....: 7.: 0.0254 m, 2.54 cm

Pound, avdp 0.453 592 37 kg, 453.592 37 g Reprinted from NBS Technical News Bulletin, March 1971. Supersedes NBS Misc PubL 253. For sale by Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20234. (Order by SD Catalog No C 13 10/344.) Price 10 cents ea.. $6.25 per 100.
To find the most up-to-date data-

(for FUNDAMENTAL PHYSICAL CONSTANTS)

http:/physics.nist.gov/PhysRefData/codata86/article.html

(for PHYSICAL REFERENCE DATA) I http:/physics.nist.gov/PhysRefData/codata86/contents.htmll

U.S. DEPARTMENT OF COMMERCE GENERAL PHYSICAL CONSTANTS National Bureau of Standards

Speed (if light in vacuum

Elementary charge Avogadro constant Atomic mass unil Elect ron rest mass

Faraday constant Planck constant Fine structure constant Charge to mass ratio for elect Rydberg constant (iyromagnetic ratio of prtilon (uncorrected for diamag.. H^O)

Bohr magneton Gas cimstant Boitzmann constant

First radiation constant {2nhc-).... Second radiation constant

Slefan Boltzmann constant

(>raviiatiimal constant

2.997 925 0

1.602 191 7 4.803 250

6.022 169

1.660 531 9.109 558

1.672 614

9.648 670

6.626 1%

7.297 351

1.758 802 8

5.272 759

1.097 373 12 2.675 196 5

2.675 127 0

9.274 0%

8.314 34

1.380 622

3.741 844

1.438 833

5.669 61 6.673 2

Uncertainly* Units: Systeme

Internal. (SI)

10" 10"

lO"

10 "

lO" 10 "

10 » 10"

kg

k(i kgC/mol Js

C/kg

10' m-'

10* rads-'T10» rads-'T- 10" J/T

10« JK'mol- 10" J/K

10-'» Wm»

10-2

10"» W m-»K

10" Nm»/kg»

'Based on 1 sid. dev.; applies to last digits in preceding column. tEleclromag. system. tElecl **These values may be in conflict with data available since the Taylor, Parker, Langenberg review. Pending a complete new readjustment of the constants, it would be prudent to multiply the above uncertainties by 3. GPO : 1971 OL- 439-689